COVID-19 impact: We are still operating and shipping all orders! Physical operations are reduced to a skeleton crew, so for critical requirements, including fighting COVID-19, please contact us so we can identify priorities. Click here for more info.

Comments by Jan

  • Coronavirus impact update: still shipping all orders

    Coronavirus impact update: still shipping all orders

    - 1 April 2020

    Tim,

    Thanks for sharing! This lines up with what our bank rep is telling us, and we're working with them to be ready to apply as soon as they start accepting applications. It's a little scary the way one loan might exclude you from another one, but it sounds like the banks and SBA will try to coordinate to maximize applicable loans without lending money twice for the same purpose. I hope it works out in practice! So far, it seems like everyone is working hard to make things better, which is nice.

    I hope you and your business make it through, too!

    - Jan

  • Coronavirus impact update: still shipping all orders

    Coronavirus impact update: still shipping all orders

    - 31 March 2020

    Hi, HEX.

    Thanks for your concern and suggestion. I am hoping that what we need (and what I am asking for) is relatively short-term help to get through the effects of all these shutdowns.

    We are working on making sure we don't lose our building and our employees don't lose medical coverage and can get money to cover their basic bills. By maintaining operations, we are able to keep shipping products that we already know how to make to people all over the world who need them, both directly in this crisis and in other essential applications. Some of our engineers who are at home and are not dealing with immediate ramifications of the emergency state in their personal lives and Pololu's operations are looking at various projects to contribute to the fight against the coronavirus. But even if we could instantly be producing ventilators and face masks, that doesn't cover the employees who cannot come to work right now because they are in higher risk groups or have to take care of their kids that are not in school.

    A "business model pivot" would be a longer-term consideration and more pressing if the disruption were more specific to our business rather than something affecting the whole global economy and which we hope the planet can recover from within a few months. If we knew now that the shutdowns were going to last for a year or more or if we had nothing else to do, then sure, it would make sense to think about completely changing the point of the business. If this current state became permanent, though, we're also talking about a world where most of Boeing and other huge companies full of smart engineers wouldn't need to exist, and all these Tesla and GM and MyPillow factories in the news retooling to make critical supplies would keep making them, so it's not clear we'd have some strategic advantage.

    That said, if you know of existing products we have that are directly relevant to this current situation, by all means please let us know! Part of the (temporary, I hope) problem is even the supply chain you mention is broken globally right now, so we largely have to make do with what we already have in the building. Given that that is a limited resource, we definitely would like them going to the most valuable applications.

    - Jan

  • Coronavirus impact update: still shipping all orders

    Coronavirus impact update: still shipping all orders

    - 30 March 2020

    Jon,

    Thanks for that advice. It's in line with other things I've heard that make gift certificates unattractive and why I've avoided offering them in the past. I also prefer to avoid the open-ended commitment, and my understanding is that Nevada's escheatment laws would make us owe most of the money to the state if we had an expiration date on the gift certificates.

    - Jan

  • Coronavirus update - please help Pololu survive

    Coronavirus update - please help Pololu survive

    - 29 March 2020

    Hello, Jon.

    Thank you for your feedback. I just posted an update, where I included quite a bit of detail about our building situation:

    https://www.pololu.com/blog/872/coronavirus-impact-update-still-shipping-all-orders

    - Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 4 March 2020

    Hello.

    AA batteries can deliver several amps. Alkalines will have a bigger voltage drop at higher loads, and this Energizer datasheet does not specify performance for more than 500mA (0.5A):

    https://data.energizer.com/pdfs/EN91.pdf

    NiMH batteries typically can provide more current, often over 5A (though of course the battery capacity will go down a lot). This datasheet, also from Energizer, shows performance for up to 4600 mA (4.6A) discharge rate:

    https://data.energizer.com/pdfs/nh15-2300.pdf

    The actual current drawn in your system is mostly dependent on your motor. If your motor draws, say, 1A at 2.5V, the batteries will usually give it that. If the motor tries to draw more than the batteries can deliver, the battery voltage will drop, which lowers what the motor draws. In the 1A at 2.5V example, your system might end up with the battery dropping to 2.0V, at which voltage the motor would draw 800mA.

    The motor driver you use should be capable of supplying the current the motor draws. 2 AA cells will give you a very low operating voltage, so that is going to limit the available motor drivers. Something like the DRV8838 or BD65496MUV might work for you:

    https://www.pololu.com/product/2990
    https://www.pololu.com/product/2960

    (Note that the drivers also need a logic supply separate from the motor supply. They can go pretty low on those two examples, but not as low as the motor supplies.)

    - Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 19 February 2020

    Hi,

    If your battery is a 12V battery, your 2500mAh divided by 80mA calculation is correct. If you are not getting around 30 hours of operation, you could measure the actual current your device is drawing to determine if it is drawing more than specified or if your battery has less capacity than specified.

    - Jan

  • New D24V150Fx 15A step-down voltage regulator family — our highest-power regulators yet!

    New D24V150Fx 15A step-down voltage regulator family — our highest-power regulators yet!

    - 6 December 2019

    Hi, Magnus.

    Things like the available space, direction of airflow, and amount of airflow you need are going to be very specific to the overall system, so I do not expect to offer a regulator like this with a particular fan as a general stock product. Can you share more about your application and what kind of a fan setup would be good for you?

    - Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 6 November 2019

    Hi, John.

    "Daisy chain" is a bad term to use in this context because it's at least ambiguous, if not outright incorrect for the setup you are describing. You can wire the batteries in series (which is what I would call daisy chaining if I had to), positive of one to negative of the other, to get 24V with 5Ah, or you can wire them in parallel, positive to positive and negative to negative, to get 12V with 10Ah. That should give you about 10% more run time than a single 9Ah battery.

    Wiring batteries in parallel makes me a bit nervous since you are initially shorting out two different voltages, but you should be ok if they are two of the same units and you charge or discharge them to the same voltage before connecting them together.

    - Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 24 October 2019

    Anonymous,

    I used eight "C" alkaline cells. Nowadays, though, I would probably just use eight NiMH AA cells since they're cheap, easy to get, and have decent capacity. The nominal voltage is a bit under 12V, so if I really needed that higher voltage, I might use ten cells.

    - Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 24 October 2019

    Brad,

    You're kind of all over the place with the units, mixing Ah and A, which is the main point of this blog post. However, for your case, most of that isn't that relevant, anyway, since you have a much more specific application, and the main challenge for you is how to charge batteries. In general, you can't just "plug in the solar panel between the batteries and the motor". Lithium-based batteries are especially touchy and dangerous, so I would stay away from them unless you have a product that is a complete solution--and then you wouldn't need to ask how to set that up.

    If this were my project and I were trying to do it cheaply/minimally, I would see if a 12V lead-acid battery would give the blinds enough juice. They might run a little slower, but probably it will be ok. Lead-acid batteries are a lot more forgiving, and a 12V battery could probably be topped off by just connecting two of your 8.4V solar panels in series and through a diode.

    - Jan

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